The present invention relates to a fat composition suitable for use in a bakery or confectionery, a bakery or confectionary product produced by using the composition and a process for preparing them. More particularly, it relates to the composition, which exerts a function of better dough improvers meeting its uses, prepared by composing a suspension, which is obtained by reacting either active substances having a function of dough improvers derived from an yeast or a mixture of an yeast and the active substances with a wheat flour, into fat. The term "fat" is used herein to include both the fatty acid triglycerides which are solid at about 20.degree. C. and triglycerides which are liquid at that temperature and which are commonly described as "oils".
A fat composition, e.g. margarine or shortening, is an important sub-material which is variously used for the preparation of dough for bakeries or confectioneries. It is known that as to a function of the fat composition, it plays very important parts such as an improvement of the extensibility of dough, an increase of a bread loaf-volume by elevating the gas retention ability in dough, a bestowal of the tolerance to mechanical treatment on dough and a retardation of the product staling.
On the other hand, an yeast is also considered to be an important sub-material, as well as a fat composition, for the preparation of bakeries or confectioneries. As the functions of the yeast for the preparation of bakeries, it is known that it exerts three functions such as a gas evolution, an activation of a dough development and a flavors formation in the course of a dough maturation processes.
The aim of the present invention is that both of the function derived from the yeast and the function of fat are combined to elevate the each peculiar function thereof synergyly and thereby to exert the functions stably.
Though, as mentioned above, it is known that fat and the yeast play a very important role for the properties of dough and the quality of a product, there are still a lot of unsolved parts as to mechanisms concerning with the dough maturation processes, e.g. the dough development and the flavors formation, in spite of many studies. For example, as to the function of fats for a dough, there are some hypotheses: the improvement of the extensibility of dough and the elevation of the gas retention ability in dough will be caused by an extention of fats along a film of gluten; the elevation of the gas retention ability will be caused by binding a lipid, which is contained in a wheat flour, with the fat composition the elevation of function of dough improvers based on fats will be caused by the interaction between fats and gluten.
As for the function of an yeast, the mechanism of the gas evolution ability is clearly known in detail, in the meantime, there remains a lot of unknown parts as to the mechanisms of the dough development, the flavors formation and so on. There are still suggested some posibilities, e.g. an activation of the dough development through metabolites, e.g. organic acids, esters or alcohols such as ethanol and an action of a reducing substances such as glutathione and cysteine or enzymes such as protease, phospholipase, invertase and maltase leaked out from an yeast cells.
The properties, which are required for a dough, such as the extensibility of dough, the tolerance to mechanical treatment and the gas retention ability are presumed to be concerned with a phenomenon of a network-forming caused by each of a dissociation (depolymerization) and a reassociation of gluten protein, and studied based on the presumption. Among substances derived from the yeast, reduced type glutathione is know to improve the extensibility of dough by either cutting the -SS- bond of gluten or depolymerizing a protein molecule through an activation of protease and it is tried to apply glutathione as a dough-improving agent for the preparation of bakeries or confectioneries. However, glutathione is expensive, therefore it is not suitable to use it on an industrial scale.
So, a disrupted yeast, which is presumed to contain glutathione, in stead of using glutathione itself, has been also employed to apply to the process for the preparation of bakeries so far.
However, both the reduced type glutathione and the disrupted yeast cells have such some disadvantages that it is very unstable since it is easily oxidized by air or decomposed by contaminants and that it is difficult to use for the preparation of bakeries since the action thereof is very rapid and it's exess-use often causes a damage on the dough.
As for substances, which are capable of advancing the dough maturation by acting on gluten contained in the wheat flour and derived from the yeast, except for glutathione, there are, as mentioned above, substances such as organic acids, alcohols and esters, which are accumulated during the dough maturation by the action of the yeast or lactic acid bacteria, and enzymes such as protease, which are able to be secreted from the yeast or lactic acid bacteria. These substances are supposed to advance the dough maturation complexly acting with the reducing substances. In this case, it should be pointed out that the substance, capable of concerning with the dough maturation, such as the reduced type glutathione and protease usually exist inside of the yeast cells and that the appearance of the enzyme activity thereof is also prevented by inhibitors, which exist inside of the yeast cells, and so on.
Therefore, it is expected to make the above mentioned substances, which are leaked out from the cells by disrupting the yeast cells, activated in order to give the more effective activities. Provided that the those active substances outside of the cells are very unstable as mentioned above, it is impossible to obtain a stable effect if protecting the substance is not considered.
Consequently, the present inventors tried to prepare a composition by emulsifying the disrupted yeast cells suspension into fats in order to protect the activities.
As a result of a test of the above mentioned try, expecting to obtain complex effects of effects such as a masking effect based on fats and an effect as an antioxidizing agent generally existed in a natural fats, expectedly, there are found a preferable preservation stability effect and, in the case of using the obtained composition for the preparation of a dough, the dough improvers effect being more effective than that in the case of using the disrupted yeast cells suspension without emulsifying it into the fats.
As a result of further study, the present invention is accomplished by finding that by producing a composition, which is prepared by reacting either the disrupted yeast cells suspension or the mixture of the disrupted yeast cells suspension and the yeast with the wheat flour, followed by emulsifying the resulting mixture into fats synergistic improved effects such as the extensibility of dough, the tolerance to mechanical treatment, the gas retention ability, the improvement of grain of crum structure and the advancement of flavors formation can be obtained by using the above obtained composition as a dough for the preparation of bakeries or confectioneries.
It is an object of the present invention to provide a fat composition for the preparation of bakeries or confectioneries, the composition being endowed with a function of dough improvers.
A further object of the present invention is to provide a method comprises advancing the stability of dough maturation by elevating the functions which are endowed by nature with the wheat flour, which is the main material of dough, the yeast and fats, which is a sub-material of dough, and thereby developing the interactions with one another beforehand.
A still further object of the present invention is to provide a method which stably maintains the activity of dough improvers derived from the yeast cells by emulsifying either into fats or by drying the emulsified fat composition to form a composition in the form of powder and thereby stably exerts the dough improvers effect for the preparation of bakeries or confectioneries.
Another object of the present invention is to provide a method which improves the properties of dough by means of the modifications, e.g. depolymerization by a reducing power, of gluten contained in the wheat flour by the activity derived from the yeast cells and thereby develops the interaction of gluten with fats.
Consequently, the present invention, according to the above objects, provides a method for preparing the products such as bakeries or confectioneries having stable qualities as well as a method useful to a rationalization such as a shortening of processes.